Question

The function below has at least one rational zero.

Use this fact to find all zeros of the function.
f(x)=7x³ +9x²-12x-4

Answer 1

Using the rational root theorem, we know to divide the function by (x - 1).

(7x³ + 9x² - 12x - 4) / (x - 1) = 7x^2 + 16x + 4

Now we can further factorize 7x^2 + 16x + 4 into (7x + 2) and (x + 2).

Therefore, the original function can be rewritten as (x - 1) (7x + 2) (x + 2).

Using the factorized form above, the zeros of the function are 1, -2/7, and -2.